Interview Questions Flashcards
What is Cryptography?
Cryptography is the practice and study of techniques for securing information and communication mainly to protect the data from third parties that the data is not intended for.
What is the difference between Symettric and Asymettric encryption?
Symettric:
* Same key for encryption/ decryption
* fast but vulnerable
* Algorithims: DES, 3DES, AES, RC4
* used for bulk data transmission
Asymettric:
* Different keys (one public and one private)
* slower due to high computation
* Algorithims: Diffie-Hellman, RSA
* Often used for securely exchanging secret keys.
What is the difference between IDS and IPS?
IDS only detects the threat where as IPS can prevent the threat.
Explain the CIA triad
Confidentiality, Integrity, and Availability
Confidentiality - Making sure only authorized users have access to the data
Integrity - Making sure the data is trustworthy and free from tampering
Availaibility - Making sure data is available to end users when its needed
How is Encryption different from Hashing?
Both change convert data into an unreadable format but encryption can be converted back to its original.
What is a firewall and why is it used?
A firewall is a security system or host based tool that monitors and controls the network traffic. They’re used to protect the system/network by monitoring incoming/outgoing network traffic and decides whether to allow or deny specific traffic based on a defined set of rules.
What is the difference between Vulnerability Assessment and Penetration Testing?
Vulnerability testing is the process of finding vulnerabilities in order to patch/fix them. Usually this is done by a tool with the correct credentials in order to log into the system.
Penetration Testing is the process of finding and exploting vulnerabilities in order to see if the testers can get past the security tools in place.
What is a three-way handshake?
A method used in a TCP/IP network to create a connection between a host and a client.
The steps are:
1. Client sends a SYN (synchronize) packet to the server in order to request esbalishing communication
2. The server responds with a SYN-ACK if it accepts the communication
3. The client acknowledges the servers response and sends an ACK (Acknowledgement) packet back to finish the handshake.
Explain SSL Encryption
- A browser tries to connect to the webserver secured with SSL
- The browser sends a copy of its SSL certificate to the browser
- The browser checks if the SSL certificate is trustworthy or not. If it is trustworthy, then the browser sends a message to the web server requesting to establish an encrypted connection
- The web server sends an acknowledgment to start an SSL encrypted connection
- SSL encrypted communication takes place between the browser and the web server
How to secure a server
- Set a secure password for root and admin accounts
- Make new accounts that will be used for managing the system and secure them.
- Remove remote access from root/admin accounts
- Configure firewall and IPtables (if linux)
- close unused ports
Explain the types of data leakage
- Accidental Breach - unintentially sending data to an anauthorized person
- Intentional breach - authorized entity sends data to an unauthorized entity on purpose
- System Hack/Breach - Hacking techniques are used to cause data leakage
What are the OSI layers
- Application Layer
- Presnetation Layer
- Session Layer
- Transport Layer
- Network Layer
- Data Link Layer
- Physical Layer - Responsible for transmission of digital data
What is a VPN?
Virtual Private Network - It is used to create a safe and encrypted connection. Data from the client is encrypted and before it gets to the server it gets decryted.
What is Risk, Vulnerability, and Threat?
- Threat - Someone with the potential to harm a system or orginization
- Vulnerability - Weakness in a system that can be exploited by a potential threat
- Risk - Potential loss or damage when a threat exploits a vulnerability
Difference between Black hat, White hat, and Gray Hat
Black Hat - Hackers that normally have the intent to do harm to a individual or company by stealing data, sabotaging websites, or disrupting communications.
White Hat - Hackers that are hired to attempt to break into a company in order to find and fix vulnerabilities and security holes.
Gray Hat - Are a mixture between White and Black hat hackers. They normally look for vulnerabilities without permission but then report it to a companies bug bounty program for rewards.
